The incisors are narrow and the molars have sharp, high crests
(Oates and Davies, 1994). This species has a dental formula of 2:1:2:3 on both
the upper and lower jaws (Ankel-Simons, 2000). The jaw is deep and the face is
short and broad (Oates and Davies, 1994). The pollex (thumb) is reduced in this
species (Davies, 1991). The orbits are widely spaced and the hind limbs are
longer as compared to the forelimbs (Oates and Davies, 1994). The average adult
body mass is 6.0 kilograms (MacKinnon and MacKinnon, 1978, 1980). The scrotum of
the male is black in coloration (Curtin, 1980). The neonate has a white
coloration with a cruciform blackish pattern on the dorsal side (Wilson and
Wilson, 1976; Aimi and Bakar, 1996).The various subspecies have different pelage colorations:Presbytis femoralis rhionis: The pelage coloration of this subspecies is
brown and grey (Wilson and Wilson, 1976). Presbytis femoralis paenulata: This subspecies has a pelage coloration
that is dark brown on the dorsal side and pale-grey brown on the ventral side
and inner limbs (Wilson and Wilson, 1976). The limbs are brown except for white
on the outer thighs (Wilson and Wilson, 1976). The hands and feet are black
(Aimi and Bakar, 1992). Surrounding the eyes there are white eye-rings and on
the top of the head there is a reduced crest (Wilson and Wilson, 1976). The lips
are flesh coloured on this subspecies (Aimi and Bakar, 1992). Presbytis femoralis perjure: This subspecies is black on both the dorsal
and ventral side except for a thin, white ventral stripe (Wilson and Wilson,
1976). There are also stripes that extend horizontally across the chest and down
the inner side of the thighs (Wilson and Wilson, 1976). The tail is black except
for the basal third that has a white ventral stripe (Aimi and Bakar, 1992). This
subspecies has narrow, pale eye-rings (Wilson and Wilson, 1976). The throat and
the face are grey in coloration (Aimi and Bakar, 1992). The chin is white (Aimi
and Bakar, 1992). Presbytis femoralis canus: The pelage coloration of this subspecies is
described as brown and grey (Wilson and Wilson, 1976). Presbytis femoralis catemana: The dorsal side and the outer surface of
the arms is drab in colour (Aimi and Bakar, 1992). The ventral side, throat, and
inner surface of the limbs are whitish in coloration (Aimi and Bakar, 1992). The
hands and feet are blackish brown (Aimi and Bakar, 1992). The tail is grey
except for the basal third that has a thin brownish line (Aimi and Bakar, 1992).
There is a broad, grey area on the outer surface of the thighs (Aimi and Bakar,
1992). The pelage of the head is blackish (Aimi and Bakar, 1992). The face is
grey with bluish eye-rings and a flesh-coloured muzzle (Aimi and Bakar, 1992).

Range:

The Banded Leaf-Monkey is found in the countries of Indonesia,
Malaysia, Singapore, and Thailand; in Indonesia this species occurs on the
islands of Borneo and Sumatra. At Ulu Kin chin, Pahang, Malaysia this species
lives in the tall forests dominated by the members of the genus Livistona where
it lives up to 400 meters in altitude (Davison, 1989). In Malaysia this species
lives in primary rainforests and can tolerate logged forests (Bennett, 1986;
Johns, 1985). Plantations were also found to be inhabited by this species in
Malaysia (Curtin, 1976). In Singapore this species is found in primary,
secondary, swamp, and dry land rainforests (Lucas et al., 1988). In Sumatra,
this species lives in mixed mangrove, primary freshwater, riverbank, primary
lowland logged, scrub-grassland riverbank, and secondary riverbank forests
(Wilson and Wilson, 1976; Crockett and Wilson, 1980).

The different subspecies of this species have different ranges:Presbytis femoralis femoralis: This subspecies is found in Singapore and
is found in the areas of Bukit Timah and Nee Soon (Lucas et al., 1988). Presbytis femoralis rhionis: This subspecies is found on Bintang Islang,
Indonesia (Yanuar, 1993/1994). This subspecies was found in lowland wetland
forest, swamp forests, secondary regrowth mixed rubber gardens, and rubber
gardens (Yanuar, 1993/1994).
Presbytis femoralis paenulata: This subspecies is found on the island of Sumatra
north of the Rokan river to the Barumun river (Wilson and Wilson, 1976). Presbytis femoralis perjure: This subspecies is found on the island of
Sumatra south of the Rokan river to the Kampar river (Wilson and Wilson, 1976).
Aimi and Bakar (1996) found that the southern distribution for this subspecies
only extends to the Siak river and not to the Kampar river. Presbytis femoralis canus: This subspecies is found on the island of
Kundur, which is in the Riau archipelago (Wilson and Wilson, 1976). This
subspecies may be found on other islands in the Riau archipelago (Wilson and
Wilson, 1976). Presbytis femoralis catemana: This subspecies is found on the island of
Sumatra south of the river Kampar to the Inderagiri river (Wilson and Wilson,
1976; Aimi and Bakar, 1992). Aimi and Bakar (1996) extends the northern range to
the Siak river.

Ecology:

The Banded Leaf-Monkey is primarily a frugivorous species that
also consumes immature leaves (Fleagle, 1978a). The seeds are the part of the
fruit most consumed. At Kuala Lompat, Malaysia, the diet of this species was
found to be composed of 42.8% fruit, 42.6% leaves, and 14.6% flowers (MacKinnon
and MacKinnon, 1980). In west Sumatra, this species was found to fed on the
leaves of the species Hevea brasiliensis and Ficus variegata (Mukhtar
et al., 1990). Although this a primarily an arboreal species, the banded
leaf-monkey has been found to come to the ground to forage for the fruits of the
species Castanopsis megacarpa and Garcinia parvifolia (Miura et al., 1997).
In Malaysia, one of the more important food species is Intsia palembanica
in which the flowers, fruits, and new and mature leaves are consumed (Curtin,
1980). At Kuala Lompat, Malaysia, this species was found to mostly forage for
young leaves and the reproductive parts of trees (Bennett, 1983; cited in
Bennett, 1986). A group of Banded Leaf-Monkeys forages together, moving from
food source to source as a cohesive unit (Fleagle, 1978a). This species spends
more time foraging in the understory as compared to the main canopy and the
emergent level (Fleagle, 1978a, b, 1976). Although Curtin (1980) found that at
Kuala Lompat this species mainly foraged in the middle story of the canopy and
the emergent level. In west Sumatra 53% of foraging occurred at the tree crowns
from heights of between 15 and 20 meters (Mukhtar et al., 1990). At Kuala Lompat
it was found that foraging mostly occurred at heights greater than 80 feet
(MacKinnon and MacKinnon, 1978). This species will sometimes break up into
subgroups when foraging (MacKinnon and MacKinnon, 1980). When feeding the Banded
Leaf-Monkey most often adopts a sitting posture (93%) over a hanging posture
(7%) (Fleagle, 1978a). At Kuala Lompat, Malaysia, this species has a mean
feeding time of 4.85 hours per day (MacKinnon and MacKinnon, 1978). Feeding is
spread out over the day probably because this species does not want to overload
the digestive system causing problems such as acidosis (MacKinnon and MacKinnon,
1980). Overall, the Banded Leaf-Monkey has a diet with greater diversity as
compared to other sympatric leaf-monkeys, such as Trachypithecus obscurus (Curtin, 1976). At Kuala Lompat, Curtin (1980, 1976) found that the diet of the
Banded Leaf-Monkey was composed of 48% fruit, 24% new leaves, 11% mature leaves,
8% seeds and beans, 6% flowers, and 2% other. The species Parkia javanica
was found to be feed upon primarily for its beans (Curtin, 1980). The species
Intsia palembanica was found to be feed upon for its seeds in
October-December, flowers in March, and mature leaves in March and October
(Curtin, 1980). The Banded Leaf-Monkey would increasingly concentrate on
foraging for fruits from April onwards until the end of the year and after July
and August, fruits made up two-thirds of the diet (Curtin, 1976).
Also at Kuala Lompat, Davies et al. (1988) found that the diet of the Banded
Leaf-Monkey is composed of 8% mature leaves, 27.7% young leaves, 11.5% flowers,
10% fruit, 25.3% seeds, 14.2% fruits and/or seeds, and 3.3 other plant parts.
The species Monocarpia marginalis is utilized heavily, with mature
leaves, young leaves, petioles of mature leaves, flowers, and fruit being
consumed (Davies et al., 1988). The species Intsia palembanica was utilized for
its young leaves, flowers, and seeds (Davies et al., 1988). Young leaves of the
species Anisoptera scaphula are an important food source for this species
(Davies et al., 1988).

The most activity for the Banded Leaf-Monkey is resting (Sewellenggam and
Bennett, 1981; Mukhtar et al., 1990). Resting was found to increase following
logging in the home range (Johns, 1986a). Adult males were found to rest more
than adult females (Sewellenggam and Bennett, 1981). There is a slight increase
in resting during the hottest part of the day, but resting decreases towards the
end of the day due to an increase in feeding (Sewellenggam and Bennett, 1981).
Members of a group will sleep and rest together (Fleagle, 1978a). Day ranging
behavior for the group consists of travelling in irregular loops in and out of
the central core area (Curtin, 1980, 1976). These loops were found to be longer
in the fruiting season (June-August) and shorter in the dry season
(January-March) (Curtin, 1980). Intensive foraging occurs in the core area
(Curtin, 1976). This species shows two major feeding peaks, one in the early
morning and one in late afternoon, with smaller feeding bout, rest, and
travelling interspersed (Curtin, 1980). Fruit is consumed more in the early
morning and early afternoon and new leaves are consumed more in the late
afternoon (Curtin, 1980). Group sizes for this species range from 2 to 8
individuals (Mukhtar et al., 1990). At Sungai Tekam, Malaysia, the mean group
size was found to be 14 individuals, with a range of 13-15 individuals (Johns,
1986a, b). At Kuala Lompat, Malaysia, the mean group size was found to be 9.3
individuals (MacKinnon and MacKinnon, 1978, 1980). At Perawang the average group
size was found to be 11 individuals (Megantara, 1989; cited in Sterck and van
Hooff, 2000). The banded leaf-monkey is arboreal and diurnal. Intergroup
encounters in the banded leaf-monkey increases at large, rare food sources
(Bennett, 1986). Adult males tend to spend more time near adult females than to
juveniles (Sewellenggam and Bennett, 1981). Juveniles, conversely, spend more
time with adult females than with adult males, but they also spend more time
with adult females than with other juveniles and the reason suggested for this
is that juveniles must learn from adult females about what foods to eat and
where to travel (Sewellenggam and Bennett, 1981). Lone males tend to be
restricted to less desirable parts of the forest being forced by resident males
of unimale groups (Bennett, 1986). This species will shift their home range
during logging and after logging (Johns, 1986a). If logging occurs in their
area, this species use the lower to middle canopy more over the upper canopy
(Johns, 1986a). There is also a shift of an increase in folivory when the home
range is logged (Johns, 1986a, b). Also after logging this species tends to
split up into subgroups for foraging whereas before the home range was logged
this species would rarely split up into subgroups (Johns, 1986a). This species
will use sleeping sites more than once (MacKinnon and MacKinnon, 1980). Sleeping
sites also tend to be in trees bordering rivers (Curtin, 1980).

Locomotion:

The Banded Leaf-Monkey moves through the forest quadrupedally
(Fleagle, 1988). During travelling in this species, quadrupedal walking and
running accounts for 20.7%, leaping 42.5%, hopping 25%, climbing 8.4%, and arm
swinging 3.4% of the locomotion (Fleagle, 1978a, b). During feeding the types of
locomotion employed includes: quadrupedal walking and running (35.5%), leaping
(10.6%), hopping (20.9%), climbing (30.1%), and arm swinging (0.9%) (Fleagle,
1978a). Quadrupedal walking and running occurs mostly on branches, with boughs
of trees being second in importance when travelling (Fleagle, 1978a, b). During
leaping, takeoff and landing occurs mostly on branches, but landing on twigs is
also important when travelling (Fleagle, 1978a, b). Also for leaping takeoff
supports tend to be larger than landing supports (Fleagle, 1978a, b). Hopping
occurs mostly on branches and boughs when travelling (Fleagle, 1978a, b). When
feeding this species tends to hop between the large parts of a tree then climb
to the smaller regions (Fleagle, 1978a). The Banded Leaf-Monkey travels through
the forest canopy at heights ranging from 5 to 30 meters (Mukhtar et al., 1990).
At Kuala Lompat, Malaysia, it was found that this species mostly travels through
the forest at heights greater than 80 feet (MacKinnon and MacKinnon, 1978).

Social Behaviour:

The Banded Leaf-Monkey has a unimale social system and a
polygynous mating system. Most social interactions in this species occur between
the adult female and juveniles (Curtin, 1976). Both males and females disperse
from their natal groups (Megantara, 1989; cited in Sterck, 1999). When males
leave they either remain solitary or join all-male groups (Bennett and Davies,
1994). This is a territorial species in which home ranges of neighbouring groups
overlap extensively (Bennett, 1985, 1986). At Kuala Lompat, there is extensive
home range overlap with some smaller groups having their entire home range
overlapped by larger groups (MacKinnon and MacKinnon, 1980). The degree of
territoriality seems to be related to food source distribution and size of food
trees where with food trees that are relatively small and are less
widely-scattered, this species tends to be more territorial (Bennett, 1985;
Johns, 1985). At Kuala Lompat, groups of banded leaf-monkeys tend to be more
tolerant of each other when they come into contact because food trees are large,
seasonal, and rare, but at Sungai Tekam groups are more territorial because the
food trees are small and less widely-scattered (Bennett, 1985, 1986). Adult
males will maintain territorial boundaries by calling, displaying, and
confronting neighbouring adult males (Curtin, 1980). Adult males will also defend
the group against predators by calling, either the whuh or the churr-r-r-r call,
and by displaying, drawing the predator away from the group that remains hidden
and silent (Curtin, 1980). The Crab-Eating Macaque, Macaca fascicularis, has
been found to displace this species from feeding sites and from night sleeping
sites (MacKinnon and MacKinnon, 1978). Even though the Crab-Eating Macaque is
smaller than the Banded Leaf-Monkey, it might be able to displace it because of
having a larger group size and an increase of aggressiveness (MacKinnon and
MacKinnon, 1980).

Vocal Communication:Loud calls: This call serves to communicate territoriality. The Banded
Leaf-Monkey tends to emit this call from emergent legumes and dipterocarps and
calling trees tend to be sleeping trees (Johns, 1985). This call is given by the
adult male in a unimale group and is given at dawn, dusk, and throughout the
night (Bennett, 1986). This call is described as sounding like "churr-r-r,
churr-r-r, ka-ka-ka" (Curtin, 1980).whuh: This call is given by a group member when faced with a mild
disturbance (Curtin, 1980). This is given at the presence of a predator (Curtin,
1980).
churr-r-r-r: This call is given by a group member when faced with a severe
disturbance (Curtin, 1980). This is given at the presence of a predator (Curtin,
1980).
Social grooming: This is when one individual grooms another
and is used to reinforce the bonds between individuals.

Reproduction:

The Banded Leaf-Monkey gives birth to a single offspring,
although twins have occurred in the wild (Bennett, 1988). Estrus occurs for 5 to
7 days every 30 days (Pitra et al., 1995). There are no external sign of estrus
in this species (Newton and Dunbar, 1994). The gestation period of this species
is 168 days and the interbirth interval is about 2 years (Pitra et al., 1995).
Births for this species can occur in most months of the year (Pitra et al.,
1995). Lactation in the Banded Leaf-Monkey occurs for 10 to 12 months (Pitra et
al., 1995). In this species infant transfer is rare, but when one mother gave
birth to twins, he often gave one of the twins to another to carry it (Bennett,
1988). Allomothering increases with the birth of twins where adult females care
for infants and when they become older, juveniles of both sexes start to care
for them (Bennett, 1988). Allomothering, or alloparental care, may increase
because it is difficult for a mother to travel and forage for food with having
two infants to hold (Bennett, 1988). As twins become older allomothering by
adult females decreases while that of juveniles increases (Bennett, 1988). Twins
tend to stay with their mothers for a longer period of time as compared to
single young, they become independent at a later age compared to single young
(Bennett, 1988).

This species is listed as CITES Appendix II. It presumably
occurs in a number of protected areas. Further studies are needed into the
taxonomy, distribution, abundance, and threats to this species. There is an
urgent need to clarify the taxonomy and distribution of what is now considered
P. femoralis, as there is very little information at this time. Since siamensis
has been separated from femoralis, there has been confusion about what is known
of femoralis, and what of that actually pertains to siamensis.